elfexec_test.go

Documentation: github.com/google/pprof/internal/elfexec

     1  // Copyright 2014 Google Inc. All Rights Reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package elfexec
    16  
    17  import (
    18  	"debug/elf"
    19  	"fmt"
    20  	"reflect"
    21  	"strings"
    22  	"testing"
    23  )
    24  
    25  func TestGetBase(t *testing.T) {
    26  
    27  	fhExec := &elf.FileHeader{
    28  		Type: elf.ET_EXEC,
    29  	}
    30  	fhRel := &elf.FileHeader{
    31  		Type: elf.ET_REL,
    32  	}
    33  	fhDyn := &elf.FileHeader{
    34  		Type: elf.ET_DYN,
    35  	}
    36  	lsOffset := &elf.ProgHeader{
    37  		Vaddr: 0x400000,
    38  		Off:   0x200000,
    39  	}
    40  	kernelHeader := &elf.ProgHeader{
    41  		Vaddr: 0xffffffff81000000,
    42  	}
    43  	kernelAslrHeader := &elf.ProgHeader{
    44  		Vaddr: 0xffffffff80200000,
    45  		Off:   0x1000,
    46  	}
    47  	// Kernel PIE header with vaddr aligned to a 4k boundary
    48  	kernelPieAlignedHeader := &elf.ProgHeader{
    49  		Vaddr: 0xffff000010080000,
    50  		Off:   0x10000,
    51  	}
    52  	// Kernel PIE header with vaddr that doesn't fall on a 4k boundary
    53  	kernelPieUnalignedHeader := &elf.ProgHeader{
    54  		Vaddr: 0xffffffc010080800,
    55  		Off:   0x10800,
    56  	}
    57  	ppc64KernelHeader := &elf.ProgHeader{
    58  		Vaddr: 0xc000000000000000,
    59  	}
    60  
    61  	testcases := []struct {
    62  		label                string
    63  		fh                   *elf.FileHeader
    64  		loadSegment          *elf.ProgHeader
    65  		stextOffset          *uint64
    66  		start, limit, offset uint64
    67  		want                 uint64
    68  		wanterr              bool
    69  	}{
    70  		{"exec", fhExec, nil, nil, 0x400000, 0, 0, 0, false},
    71  		{"exec offset", fhExec, lsOffset, nil, 0x400000, 0x800000, 0, 0x200000, false},
    72  		{"exec offset 2", fhExec, lsOffset, nil, 0x200000, 0x600000, 0, 0, false},
    73  		{"exec nomap", fhExec, nil, nil, 0, 0, 0, 0, false},
    74  		{"exec kernel", fhExec, kernelHeader, uint64p(0xffffffff81000198), 0xffffffff82000198, 0xffffffff83000198, 0, 0x1000000, false},
    75  		{"exec kernel", fhExec, kernelHeader, uint64p(0xffffffff810002b8), 0xffffffff81000000, 0xffffffffa0000000, 0x0, 0x0, false},
    76  		{"exec kernel ASLR", fhExec, kernelHeader, uint64p(0xffffffff810002b8), 0xffffffff81000000, 0xffffffffa0000000, 0xffffffff81000000, 0x0, false},
    77  		// TODO(aalexand): Figure out where this test case exactly comes from and
    78  		// whether it's still relevant.
    79  		{"exec kernel ASLR 2", fhExec, kernelAslrHeader, nil, 0xffffffff83e00000, 0xfffffffffc3fffff, 0x3c00000, 0x3c00000, false},
    80  		{"exec PPC64 kernel", fhExec, ppc64KernelHeader, uint64p(0xc000000000000000), 0xc000000000000000, 0xd00000001a730000, 0x0, 0x0, false},
    81  		{"exec chromeos kernel", fhExec, kernelHeader, uint64p(0xffffffff81000198), 0, 0x10197, 0, 0x7efffe68, false},
    82  		{"exec chromeos kernel 2", fhExec, kernelHeader, uint64p(0xffffffff81000198), 0, 0x10198, 0, 0x7efffe68, false},
    83  		{"exec chromeos kernel 3", fhExec, kernelHeader, uint64p(0xffffffff81000198), 0x198, 0x100000, 0, 0x7f000000, false},
    84  		{"exec chromeos kernel 4", fhExec, kernelHeader, uint64p(0xffffffff81200198), 0x198, 0x100000, 0, 0x7ee00000, false},
    85  		{"exec chromeos kernel unremapped", fhExec, kernelHeader, uint64p(0xffffffff810001c8), 0xffffffff834001c8, 0xffffffffc0000000, 0xffffffff834001c8, 0x2400000, false},
    86  		{"dyn", fhDyn, nil, nil, 0x200000, 0x300000, 0, 0x200000, false},
    87  		{"dyn map", fhDyn, lsOffset, nil, 0x0, 0x300000, 0, 0xFFFFFFFFFFE00000, false},
    88  		{"dyn nomap", fhDyn, nil, nil, 0x0, 0x0, 0, 0, false},
    89  		{"dyn map+offset", fhDyn, lsOffset, nil, 0x900000, 0xa00000, 0x200000, 0x500000, false},
    90  		{"dyn kernel", fhDyn, kernelPieAlignedHeader, uint64p(0xffff000010080000), 0xffff000010080000, 0xffffffffffffffff, 0xffff000010080000, 0, false},
    91  		{"dyn chromeos aslr kernel", fhDyn, kernelPieUnalignedHeader, uint64p(0xffffffc010080800), 0x800, 0xb7f800, 0, 0x3feff80000, false},
    92  		{"dyn chromeos aslr kernel unremapped", fhDyn, kernelPieUnalignedHeader, uint64p(0xffffffc010080800), 0xffffffdb5d680800, 0xffffffdb5e200000, 0xffffffdb5d680800, 0x1b4d600000, false},
    93  		{"rel", fhRel, nil, nil, 0x2000000, 0x3000000, 0, 0x2000000, false},
    94  		{"rel nomap", fhRel, nil, nil, 0x0, ^uint64(0), 0, 0, false},
    95  		{"rel offset", fhRel, nil, nil, 0x100000, 0x200000, 0x1, 0, true},
    96  	}
    97  
    98  	for _, tc := range testcases {
    99  		base, err := GetBase(tc.fh, tc.loadSegment, tc.stextOffset, tc.start, tc.limit, tc.offset)
   100  		if err != nil {
   101  			if !tc.wanterr {
   102  				t.Errorf("%s: want no error, got %v", tc.label, err)
   103  			}
   104  			continue
   105  		}
   106  		if tc.wanterr {
   107  			t.Errorf("%s: want error, got nil", tc.label)
   108  			continue
   109  		}
   110  		if base != tc.want {
   111  			t.Errorf("%s: want 0x%x, got 0x%x", tc.label, tc.want, base)
   112  		}
   113  	}
   114  }
   115  
   116  func uint64p(n uint64) *uint64 {
   117  	return &n
   118  }
   119  
   120  func TestFindProgHeaderForMapping(t *testing.T) {
   121  	buildList := func(headers []*elf.ProgHeader) (result string) {
   122  		builder := strings.Builder{}
   123  		if err := builder.WriteByte('['); err != nil {
   124  			t.Error("Failed to append '[' to the builder")
   125  		}
   126  		defer func() {
   127  			if err := builder.WriteByte(']'); err != nil {
   128  				t.Error("Failed to append ']' to the builder")
   129  			}
   130  			result = builder.String()
   131  		}()
   132  		if len(headers) == 0 {
   133  			if _, err := builder.WriteString("nil"); err != nil {
   134  				t.Error("Failed to append 'nil' to the builder")
   135  			}
   136  			return
   137  		}
   138  		if _, err := builder.WriteString(fmt.Sprintf("%#v", *headers[0])); err != nil {
   139  			t.Error("Failed to append first header to the builder")
   140  		}
   141  		for i, h := range headers[1:] {
   142  			if _, err := builder.WriteString(fmt.Sprintf(", %#v", *h)); err != nil {
   143  				t.Errorf("Failed to append header %d to the builder", i+1)
   144  			}
   145  		}
   146  		return
   147  	}
   148  
   149  	// Variuos ELF program headers for unit tests.
   150  	tinyHeaders := []elf.ProgHeader{
   151  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000},
   152  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x1f0, Memsz: 0x1f0, Align: 0x200000},
   153  	}
   154  	tinyBadBSSHeaders := []elf.ProgHeader{
   155  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000},
   156  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x100, Memsz: 0x1f0, Align: 0x200000},
   157  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xd80, Vaddr: 0x400d80, Paddr: 0x400d80, Filesz: 0x90, Memsz: 0x90, Align: 0x200000},
   158  	}
   159  	smallHeaders := []elf.ProgHeader{
   160  		{Type: elf.PT_PHDR, Flags: elf.PF_R | elf.PF_X, Off: 0x40, Vaddr: 0x400040, Paddr: 0x400040, Filesz: 0x1f8, Memsz: 0x1f8, Align: 8},
   161  		{Type: elf.PT_INTERP, Flags: elf.PF_R, Off: 0x238, Vaddr: 0x400238, Paddr: 0x400238, Filesz: 0x1c, Memsz: 0x1c, Align: 1},
   162  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0x400000, Paddr: 0x400000, Filesz: 0x6fc, Memsz: 0x6fc, Align: 0x200000},
   163  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe10, Vaddr: 0x600e10, Paddr: 0x600e10, Filesz: 0x230, Memsz: 0x238, Align: 0x200000},
   164  		{Type: elf.PT_DYNAMIC, Flags: elf.PF_R | elf.PF_W, Off: 0xe28, Vaddr: 0x600e28, Paddr: 0x600e28, Filesz: 0x1d0, Memsz: 0x1d0, Align: 8},
   165  	}
   166  	smallBadBSSHeaders := []elf.ProgHeader{
   167  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0x200000, Paddr: 0x200000, Filesz: 0x6fc, Memsz: 0x6fc, Align: 0x200000},
   168  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0x700, Vaddr: 0x400700, Paddr: 0x400700, Filesz: 0x500, Memsz: 0x710, Align: 0x200000},
   169  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe10, Vaddr: 0x600e10, Paddr: 0x600e10, Filesz: 0x230, Memsz: 0x238, Align: 0x200000},
   170  	}
   171  	mediumHeaders := []elf.ProgHeader{
   172  		{Type: elf.PT_PHDR, Flags: elf.PF_R, Off: 0x40, Vaddr: 0x40, Paddr: 0x40, Filesz: 0x268, Memsz: 0x268, Align: 8},
   173  		{Type: elf.PT_INTERP, Flags: elf.PF_R, Off: 0x2a8, Vaddr: 0x2a8, Paddr: 0x2a8, Filesz: 0x28, Memsz: 0x28, Align: 1},
   174  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0x51800, Memsz: 0x51800, Align: 0x200000},
   175  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0x51800, Vaddr: 0x251800, Paddr: 0x251800, Filesz: 0x24a8, Memsz: 0x24e8, Align: 0x200000},
   176  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0x53d00, Vaddr: 0x453d00, Paddr: 0x453d00, Filesz: 0x13a58, Memsz: 0x91a198, Align: 0x200000},
   177  		{Type: elf.PT_TLS, Flags: elf.PF_R, Off: 0x51800, Vaddr: 0x51800, Paddr: 0x51800, Filesz: 0x0, Memsz: 0x38, Align: 0x8},
   178  		{Type: elf.PT_DYNAMIC, Flags: elf.PF_R | elf.PF_W, Off: 0x51d00, Vaddr: 0x251d00, Paddr: 0x251d00, Filesz: 0x1ef0, Memsz: 0x1ef0, Align: 8},
   179  	}
   180  	largeHeaders := []elf.ProgHeader{
   181  		{Type: elf.PT_PHDR, Flags: elf.PF_R, Off: 0x40, Vaddr: 0x40, Paddr: 0x40, Filesz: 0x268, Memsz: 0x268, Align: 8},
   182  		{Type: elf.PT_INTERP, Flags: elf.PF_R, Off: 0x2a8, Vaddr: 0x2a8, Paddr: 0x2a8, Filesz: 0x28, Memsz: 0x28, Align: 1},
   183  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0x2ec5d2c0, Memsz: 0x2ec5d2c0, Align: 0x200000},
   184  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0x2ec5d2c0, Vaddr: 0x2ee5d2c0, Paddr: 0x2ee5d2c0, Filesz: 0x1361118, Memsz: 0x1361150, Align: 0x200000},
   185  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0x2ffbe440, Vaddr: 0x303be440, Paddr: 0x303be440, Filesz: 0x4637c0, Memsz: 0xc91610, Align: 0x200000},
   186  		{Type: elf.PT_TLS, Flags: elf.PF_R, Off: 0x2ec5d2c0, Vaddr: 0x2ee5d2c0, Paddr: 0x2ee5d2c0, Filesz: 0x120, Memsz: 0x103f8, Align: 0x40},
   187  		{Type: elf.PT_DYNAMIC, Flags: elf.PF_R | elf.PF_W, Off: 0x2ffbc9e0, Vaddr: 0x301bc9e0, Paddr: 0x301bc9e0, Filesz: 0x1f0, Memsz: 0x1f0, Align: 8},
   188  	}
   189  	ffmpegHeaders := []elf.ProgHeader{
   190  		{Type: elf.PT_PHDR, Flags: elf.PF_R, Off: 0x40, Vaddr: 0x200040, Paddr: 0x200040, Filesz: 0x1f8, Memsz: 0x1f8, Align: 8},
   191  		{Type: elf.PT_INTERP, Flags: elf.PF_R, Off: 0x238, Vaddr: 0x200238, Paddr: 0x200238, Filesz: 0x28, Memsz: 0x28, Align: 1},
   192  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0x200000, Paddr: 0x200000, Filesz: 0x48d8410, Memsz: 0x48d8410, Align: 0x200000},
   193  		{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0x48d8440, Vaddr: 0x4cd8440, Paddr: 0x4cd8440, Filesz: 0x18cbe0, Memsz: 0xd2fb70, Align: 0x200000},
   194  		{Type: elf.PT_TLS, Flags: elf.PF_R, Off: 0x48d8440, Vaddr: 0x4cd8440, Paddr: 0x4cd8440, Filesz: 0xa8, Memsz: 0x468, Align: 0x40},
   195  		{Type: elf.PT_DYNAMIC, Flags: elf.PF_R | elf.PF_W, Off: 0x4a63ad0, Vaddr: 0x4e63ad0, Paddr: 0x4e63ad0, Filesz: 0x200, Memsz: 0x200, Align: 8},
   196  	}
   197  	sentryHeaders := []elf.ProgHeader{
   198  		{Type: elf.PT_LOAD, Flags: elf.PF_X + elf.PF_R, Off: 0x0, Vaddr: 0x7f0000000000, Paddr: 0x7f0000000000, Filesz: 0xbc64d5, Memsz: 0xbc64d5, Align: 0x1000},
   199  		{Type: elf.PT_LOAD, Flags: elf.PF_R, Off: 0xbc7000, Vaddr: 0x7f0000bc7000, Paddr: 0x7f0000bc7000, Filesz: 0xcd6b30, Memsz: 0xcd6b30, Align: 0x1000},
   200  		{Type: elf.PT_LOAD, Flags: elf.PF_W + elf.PF_R, Off: 0x189e000, Vaddr: 0x7f000189e000, Paddr: 0x7f000189e000, Filesz: 0x58180, Memsz: 0x92d10, Align: 0x1000},
   201  	}
   202  
   203  	for _, tc := range []struct {
   204  		desc        string
   205  		phdrs       []elf.ProgHeader
   206  		pgoff       uint64
   207  		memsz       uint64
   208  		wantHeaders []*elf.ProgHeader
   209  	}{
   210  		{
   211  			desc:        "no prog headers",
   212  			phdrs:       nil,
   213  			pgoff:       0,
   214  			memsz:       0x1000,
   215  			wantHeaders: nil,
   216  		},
   217  		{
   218  			desc:  "tiny file, 4KB at offset 0 matches both headers, b/178747588",
   219  			phdrs: tinyHeaders,
   220  			pgoff: 0,
   221  			memsz: 0x1000,
   222  			wantHeaders: []*elf.ProgHeader{
   223  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000},
   224  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x1f0, Memsz: 0x1f0, Align: 0x200000},
   225  			},
   226  		},
   227  		{
   228  			desc:        "tiny file, file offset 4KB matches no headers",
   229  			phdrs:       tinyHeaders,
   230  			pgoff:       0x1000,
   231  			memsz:       0x1000,
   232  			wantHeaders: nil,
   233  		},
   234  		{
   235  			desc:        "tiny file with unaligned memsz matches executable segment",
   236  			phdrs:       tinyHeaders,
   237  			pgoff:       0,
   238  			memsz:       0xc80,
   239  			wantHeaders: []*elf.ProgHeader{{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000}},
   240  		},
   241  		{
   242  			desc:        "tiny file with unaligned offset matches data segment",
   243  			phdrs:       tinyHeaders,
   244  			pgoff:       0xc80,
   245  			memsz:       0x1000,
   246  			wantHeaders: []*elf.ProgHeader{{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x1f0, Memsz: 0x1f0, Align: 0x200000}},
   247  		},
   248  		{
   249  			desc:  "tiny bad BSS file, 4KB at offset 0 matches all three headers",
   250  			phdrs: tinyBadBSSHeaders,
   251  			pgoff: 0,
   252  			memsz: 0x1000,
   253  			wantHeaders: []*elf.ProgHeader{
   254  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000},
   255  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x100, Memsz: 0x1f0, Align: 0x200000},
   256  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xd80, Vaddr: 0x400d80, Paddr: 0x400d80, Filesz: 0x90, Memsz: 0x90, Align: 0x200000},
   257  			},
   258  		},
   259  		{
   260  			desc:  "small file, offset 0, memsz 4KB matches both segments",
   261  			phdrs: smallHeaders,
   262  			pgoff: 0,
   263  			memsz: 0x1000,
   264  			wantHeaders: []*elf.ProgHeader{
   265  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0x400000, Paddr: 0x400000, Filesz: 0x6fc, Memsz: 0x6fc, Align: 0x200000},
   266  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe10, Vaddr: 0x600e10, Paddr: 0x600e10, Filesz: 0x230, Memsz: 0x238, Align: 0x200000},
   267  			},
   268  		},
   269  		{
   270  			desc:  "small file, offset 0, memsz 8KB matches both segments",
   271  			phdrs: smallHeaders,
   272  			pgoff: 0,
   273  			memsz: 0x2000,
   274  			wantHeaders: []*elf.ProgHeader{
   275  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0x400000, Paddr: 0x400000, Filesz: 0x6fc, Memsz: 0x6fc, Align: 0x200000},
   276  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe10, Vaddr: 0x600e10, Paddr: 0x600e10, Filesz: 0x230, Memsz: 0x238, Align: 0x200000},
   277  			},
   278  		},
   279  		{
   280  			desc:        "small file, offset 4KB matches data segment",
   281  			phdrs:       smallHeaders,
   282  			pgoff:       0x1000,
   283  			memsz:       0x1000,
   284  			wantHeaders: []*elf.ProgHeader{{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe10, Vaddr: 0x600e10, Paddr: 0x600e10, Filesz: 0x230, Memsz: 0x238, Align: 0x200000}},
   285  		},
   286  		{
   287  			desc:        "small file, offset 8KB matches no segment",
   288  			phdrs:       smallHeaders,
   289  			pgoff:       0x2000,
   290  			memsz:       0x1000,
   291  			wantHeaders: nil,
   292  		},
   293  		{
   294  			desc:  "small bad BSS file, offset 0, memsz 4KB matches all three segments",
   295  			phdrs: smallBadBSSHeaders,
   296  			pgoff: 0,
   297  			memsz: 0x1000,
   298  			wantHeaders: []*elf.ProgHeader{
   299  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0x200000, Paddr: 0x200000, Filesz: 0x6fc, Memsz: 0x6fc, Align: 0x200000},
   300  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0x700, Vaddr: 0x400700, Paddr: 0x400700, Filesz: 0x500, Memsz: 0x710, Align: 0x200000},
   301  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe10, Vaddr: 0x600e10, Paddr: 0x600e10, Filesz: 0x230, Memsz: 0x238, Align: 0x200000},
   302  			},
   303  		},
   304  		{
   305  			desc:  "small bad BSS file, offset 0, memsz 8KB matches all three segments",
   306  			phdrs: smallBadBSSHeaders,
   307  			pgoff: 0,
   308  			memsz: 0x2000,
   309  			wantHeaders: []*elf.ProgHeader{
   310  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0x200000, Paddr: 0x200000, Filesz: 0x6fc, Memsz: 0x6fc, Align: 0x200000},
   311  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0x700, Vaddr: 0x400700, Paddr: 0x400700, Filesz: 0x500, Memsz: 0x710, Align: 0x200000},
   312  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe10, Vaddr: 0x600e10, Paddr: 0x600e10, Filesz: 0x230, Memsz: 0x238, Align: 0x200000},
   313  			},
   314  		},
   315  		{
   316  			desc:        "small bad BSS file, offset 4KB matches second data segment",
   317  			phdrs:       smallBadBSSHeaders,
   318  			pgoff:       0x1000,
   319  			memsz:       0x1000,
   320  			wantHeaders: []*elf.ProgHeader{{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe10, Vaddr: 0x600e10, Paddr: 0x600e10, Filesz: 0x230, Memsz: 0x238, Align: 0x200000}},
   321  		},
   322  		{
   323  			desc:        "medium file large mapping that includes all address space matches executable segment, b/179920361",
   324  			phdrs:       mediumHeaders,
   325  			pgoff:       0,
   326  			memsz:       0xd6e000,
   327  			wantHeaders: []*elf.ProgHeader{{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0x51800, Memsz: 0x51800, Align: 0x200000}},
   328  		},
   329  		{
   330  			desc:        "large file executable mapping matches executable segment",
   331  			phdrs:       largeHeaders,
   332  			pgoff:       0,
   333  			memsz:       0x2ec5e000,
   334  			wantHeaders: []*elf.ProgHeader{{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0x2ec5d2c0, Memsz: 0x2ec5d2c0, Align: 0x200000}},
   335  		},
   336  		{
   337  			desc:        "large file first data mapping matches first data segment",
   338  			phdrs:       largeHeaders,
   339  			pgoff:       0x2ec5d000,
   340  			memsz:       0x1362000,
   341  			wantHeaders: []*elf.ProgHeader{{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0x2ec5d2c0, Vaddr: 0x2ee5d2c0, Paddr: 0x2ee5d2c0, Filesz: 0x1361118, Memsz: 0x1361150, Align: 0x200000}},
   342  		},
   343  		{
   344  			desc:        "large file, split second data mapping matches second data segment",
   345  			phdrs:       largeHeaders,
   346  			pgoff:       0x2ffbe000,
   347  			memsz:       0xb11000,
   348  			wantHeaders: []*elf.ProgHeader{{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0x2ffbe440, Vaddr: 0x303be440, Paddr: 0x303be440, Filesz: 0x4637c0, Memsz: 0xc91610, Align: 0x200000}},
   349  		},
   350  		{
   351  			desc:        "sentry headers, mapping for last page of executable segment matches executable segment",
   352  			phdrs:       sentryHeaders,
   353  			pgoff:       0xbc6000,
   354  			memsz:       0x1000,
   355  			wantHeaders: []*elf.ProgHeader{{Type: elf.PT_LOAD, Flags: elf.PF_X + elf.PF_R, Off: 0x0, Vaddr: 0x7f0000000000, Paddr: 0x7f0000000000, Filesz: 0xbc64d5, Memsz: 0xbc64d5, Align: 0x1000}},
   356  		},
   357  		{
   358  			desc:        "ffmpeg headers, split mapping for executable segment matches executable segment, b/193176694",
   359  			phdrs:       ffmpegHeaders,
   360  			pgoff:       0,
   361  			memsz:       0x48d8000,
   362  			wantHeaders: []*elf.ProgHeader{{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0x200000, Paddr: 0x200000, Filesz: 0x48d8410, Memsz: 0x48d8410, Align: 0x200000}},
   363  		},
   364  		{
   365  			desc: "segments with no file bits (b/195427553), mapping for executable segment matches executable segment",
   366  			phdrs: []elf.ProgHeader{
   367  				{Type: elf.PT_LOAD, Flags: elf.PF_R, Off: 0x0, Vaddr: 0x0, Paddr: 0x0, Filesz: 0x115000, Memsz: 0x115000, Align: 0x1000},
   368  				{Type: elf.PT_LOAD, Flags: elf.PF_X + elf.PF_R, Off: 0x115000, Vaddr: 0x115000, Paddr: 0x115000, Filesz: 0x361e15, Memsz: 0x361e15, Align: 0x1000},
   369  				{Type: elf.PT_LOAD, Flags: elf.PF_W + elf.PF_R, Off: 0x0, Vaddr: 0x477000, Paddr: 0x477000, Filesz: 0x0, Memsz: 0x33c, Align: 0x1000},
   370  				{Type: elf.PT_LOAD, Flags: elf.PF_R, Off: 0x0, Vaddr: 0x478000, Paddr: 0x478000, Filesz: 0x0, Memsz: 0x47dc28, Align: 0x1000},
   371  				{Type: elf.PT_LOAD, Flags: elf.PF_R, Off: 0x477000, Vaddr: 0x8f6000, Paddr: 0x8f6000, Filesz: 0x140, Memsz: 0x140, Align: 0x1000},
   372  				{Type: elf.PT_LOAD, Flags: elf.PF_W + elf.PF_R, Off: 0x478000, Vaddr: 0x8f7000, Paddr: 0x8f7000, Filesz: 0x38, Memsz: 0x38, Align: 0x1000},
   373  			},
   374  			pgoff:       0x115000,
   375  			memsz:       0x362000,
   376  			wantHeaders: []*elf.ProgHeader{{Type: elf.PT_LOAD, Flags: elf.PF_X + elf.PF_R, Off: 0x115000, Vaddr: 0x115000, Paddr: 0x115000, Filesz: 0x361e15, Memsz: 0x361e15, Align: 0x1000}},
   377  		},
   378  	} {
   379  		t.Run(tc.desc, func(t *testing.T) {
   380  			gotHeaders := ProgramHeadersForMapping(tc.phdrs, tc.pgoff, tc.memsz)
   381  			if !reflect.DeepEqual(gotHeaders, tc.wantHeaders) {
   382  				t.Errorf("got program headers %q; want %q", buildList(gotHeaders), buildList(tc.wantHeaders))
   383  			}
   384  		})
   385  	}
   386  }
   387  
   388  func TestHeaderForFileOffset(t *testing.T) {
   389  	for _, tc := range []struct {
   390  		desc       string
   391  		headers    []*elf.ProgHeader
   392  		fileOffset uint64
   393  		wantError  bool
   394  		want       *elf.ProgHeader
   395  	}{
   396  		{
   397  			desc:      "no headers, want error",
   398  			headers:   nil,
   399  			wantError: true,
   400  		},
   401  		{
   402  			desc: "three headers, BSS in last segment, file offset selects first header",
   403  			headers: []*elf.ProgHeader{
   404  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000},
   405  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x1f0, Memsz: 0x1f0, Align: 0x200000},
   406  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe70, Vaddr: 0x400e70, Paddr: 0x400e70, Filesz: 0x90, Memsz: 0x100, Align: 0x200000},
   407  			},
   408  			fileOffset: 0xc79,
   409  			want:       &elf.ProgHeader{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000},
   410  		},
   411  		{
   412  			desc: "three headers, BSS in last segment, file offset selects second header",
   413  			headers: []*elf.ProgHeader{
   414  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000},
   415  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x1f0, Memsz: 0x1f0, Align: 0x200000},
   416  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe70, Vaddr: 0x400e70, Paddr: 0x400e70, Filesz: 0x90, Memsz: 0x100, Align: 0x200000},
   417  			},
   418  			fileOffset: 0xc80,
   419  			want:       &elf.ProgHeader{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x1f0, Memsz: 0x1f0, Align: 0x200000},
   420  		},
   421  		{
   422  			desc: "three headers, BSS in last segment, file offset selects third header",
   423  			headers: []*elf.ProgHeader{
   424  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000},
   425  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x1f0, Memsz: 0x1f0, Align: 0x200000},
   426  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe70, Vaddr: 0x400e70, Paddr: 0x400e70, Filesz: 0x90, Memsz: 0x100, Align: 0x200000},
   427  			},
   428  			fileOffset: 0xef0,
   429  			want:       &elf.ProgHeader{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe70, Vaddr: 0x400e70, Paddr: 0x400e70, Filesz: 0x90, Memsz: 0x100, Align: 0x200000},
   430  		},
   431  		{
   432  			desc: "three headers, BSS in last segment, file offset in uninitialized section selects third header",
   433  			headers: []*elf.ProgHeader{
   434  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000},
   435  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x1f0, Memsz: 0x1f0, Align: 0x200000},
   436  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe70, Vaddr: 0x400e70, Paddr: 0x400e70, Filesz: 0x90, Memsz: 0x100, Align: 0x200000},
   437  			},
   438  			fileOffset: 0xf40,
   439  			want:       &elf.ProgHeader{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe70, Vaddr: 0x400e70, Paddr: 0x400e70, Filesz: 0x90, Memsz: 0x100, Align: 0x200000},
   440  		},
   441  		{
   442  			desc: "three headers, BSS in last segment, file offset past any segment gives error",
   443  			headers: []*elf.ProgHeader{
   444  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000},
   445  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x1f0, Memsz: 0x1f0, Align: 0x200000},
   446  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xe70, Vaddr: 0x400e70, Paddr: 0x400e70, Filesz: 0x90, Memsz: 0x100, Align: 0x200000},
   447  			},
   448  			fileOffset: 0xf70,
   449  			wantError:  true,
   450  		},
   451  		{
   452  			desc: "three headers, BSS in second segment, file offset in mapped section selects second header",
   453  			headers: []*elf.ProgHeader{
   454  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000},
   455  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x100, Memsz: 0x1f0, Align: 0x200000},
   456  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xd80, Vaddr: 0x400d80, Paddr: 0x400d80, Filesz: 0x100, Memsz: 0x100, Align: 0x200000},
   457  			},
   458  			fileOffset: 0xd79,
   459  			want:       &elf.ProgHeader{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x100, Memsz: 0x1f0, Align: 0x200000},
   460  		},
   461  		{
   462  			desc: "three headers, BSS in second segment, file offset in unmapped section gives error",
   463  			headers: []*elf.ProgHeader{
   464  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_X, Off: 0, Vaddr: 0, Paddr: 0, Filesz: 0xc80, Memsz: 0xc80, Align: 0x200000},
   465  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xc80, Vaddr: 0x200c80, Paddr: 0x200c80, Filesz: 0x100, Memsz: 0x1f0, Align: 0x200000},
   466  				{Type: elf.PT_LOAD, Flags: elf.PF_R | elf.PF_W, Off: 0xd80, Vaddr: 0x400d80, Paddr: 0x400d80, Filesz: 0x100, Memsz: 0x100, Align: 0x200000},
   467  			},
   468  			fileOffset: 0xd80,
   469  			wantError:  true,
   470  		},
   471  	} {
   472  		t.Run(tc.desc, func(t *testing.T) {
   473  			got, err := HeaderForFileOffset(tc.headers, tc.fileOffset)
   474  			if (err != nil) != tc.wantError {
   475  				t.Errorf("got error %v, want any error=%v", err, tc.wantError)
   476  			}
   477  			if err != nil {
   478  				return
   479  			}
   480  			if !reflect.DeepEqual(got, tc.want) {
   481  				t.Errorf("got program header %#v, want %#v", got, tc.want)
   482  			}
   483  		})
   484  	}
   485  }
   486
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